No, Zapruder had his back to the grassy knoll. A motorcycle cop rushed up the hill and was turned back by fake secret service agents. There is no film behind that wall.
Oh yes there is. I have seen it. Have you? They usually stop before Zapruder pans there, but when they had the special exhibition of all the films taken that day in Dealey Plaza “En toto” you get a look behind the fence. It was on the 7th floor of the Book Depository. Did not know they have 7 floors? I had a banquet there one time, and went to the exhibition mentioned above.